Answer:
Step-by-step explanation:
time after 40 meters to 80 meters=12-7=5 s
distance=80-40=40 m
max. speed=40/5=8 m/s
We know that
<span>1) Kayla originally has 64b dollars
</span>2) <span>She gave 1/8 of it to Luke-----> (1/8)*64b=8b
in this moment Kayla has------> 64b-8b=56b
3) </span>Kayla spent $45
in this moment Kayla has------> 56b-$45
therefore
the answer is
(56b-$45)
When x=-1:

Ok that gives us a little more information.
If we implicitly differentiate with respect to t, from the very start, then we can apply our product rule, ya?

The right side is zero, derivative of a constant is zero.
Where x' is dx/dt and y' is dy/dt.
From here, plug in all the stuff you know:
y' = -3
x = -1
y = 4
and solve for x'.
Hope that helps!
2m: "two multiplied by m"